"Unknown Age" for babies

[slifty]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github (I've searched it).
• I agree to follow Monica's Code of Conduct.

Bug description

If a contact is less than 1 year old their age is reported as "unknown

Steps to reproduce

1. Create a new contact
2. Set their birthday to be less than 1 year ago (e.g. the previous month)
3. View the "activity in this vault" tab and they will have an unknown age. If they are family members / in a group they will not have a parenthetical (0) like other contacts with birthdays would

Expected behavior

I would expect the age to be rendered as 0 (or in terms of months)

Environment

Your own self-hosted instance (v5 a.k.a chandler version or main branch)

Version of Monica

v5-beta.3

Installation method

Docker image

Web server

Nginx

Database engine version

PostgreSQL

Additional info

No response